Several novel and potentially useful methods for the synthesis of nucleosides and nucleoside analogs will be explored. The emphasis will be on the synthesis of compounds that are of interest in cancer chemotherapy. We will study (a) syntheses of cyclonucleosides (anhydronucleosides) ad related derivatives from protected and unprotected sugars, (b) direct fusion-type syntheses of nucleosides from sugars and bases, and (c) synthesis of pseudouridine and related pyrimidine pseudo-nucleosides from simple precursors. As an approach to the development of anti-viral agents, the 2'-deoxycytidine and 2'-deoxyinosine will be prepared and used for the synthesis of the 2'-fluoro-substituted analog of poly I:poly C, a potent interferon induction, in particular the effects of 2'-substitution of cytotoxicity, induction Potency and specificity, and susceptibility to nucleases. It is hoped that this information will prove useful in the development of a potent and non-toxic anti-viral agent.